Directly Downwind Faster Than The Wind

[mijhim]

how can energy equations be applied in analyzing how is DDWFTTW- Directly Downwind Faster Than The Wind- system works?
Thank you

 

[A.T.]

Check out this paper, chapter (2.1) and (2.3):
http://orbit.dtu.dk/fedora/objects/orbit:55484/datastreams/file_3748519/content

 

[russ_watters]

The key is being very clear and consistent about what frame of reference you are analyzing it from and recognizing that constant speed motion requires no force (so any net force will cause an acceleration).

 

[A.T.]

This question was part of the American semi-final for the International Physics Olympiad. The solutions are now online (page 11):

http://www.aapt.org/physicsteam/2013/upload/E3-1-7-solutions.pdf